sensor fault AZ1-BT20 or BT20 — Exhaust air sensor not connected or defective

What does 20 mean?

The BT20 sensor, monitoring exhaust air, is not connected or defective. For ground source systems, the pump (AZ1-GP2) in FLM is blocked. For exhaust air systems, this alarm resets automatically.

• BT20 sensor is disconnected or has loose wiring.
• The sensor unit is faulty or damaged.
• Issues with sensor communication for ground source systems.

Click steps to track your progress.

1. 1

   For exhaust air systems, allow for an automatic reset.

2. 2

   For ground source systems, or if the alarm persists, power cycle the Heat Pump.

3. 3

   Check the physical connections to the BT20 sensor and ensure it is properly installed.

4. 4

   If the issue remains, contact a service technician, especially for ground source applications.